I've done a little research. It seems the system is supplied by Kapsch TrafficCom of Austria and, looking at the two ANPR systems they supply, it must be the VR-2 system (data-sheet here).

It's based on a digital colour camera with resolution of 1392x1032. The other (VDR) system uses Infrared (IR), but it looks like this one does not. The blue glow around the gantries is most probably additional illumination to improve image intensity. The use of blue might be because of its higher energy, and the camera can be fitted with a filter to respond mainly to blue. Perhaps the fact that the GP plates have blue lettering contributes to the equation.

I've done a little research. It seems the system is supplied by Kapsch TrafficCom of Austria and, looking at the two ANPR systems they supply, it must be the VR-2 system (data-sheet here).

It's based on a digital colour camera with resolution of 1392x1032. The other (VDR) system uses Infrared (IR), but it looks like this one does not. The blue glow around the gantries is most probably additional illumination to improve image intensity. The use of blue might be because of its higher energy, and the camera can be fitted with a filter to respond mainly to blue. Perhaps the fact that the GP plates have blue lettering contributes to the equation.

Does that mean it reads blue lettering more effectively? So if you have lots of blue writing near the number plate it will get confused?

I used to work in this field so I can give a basic idea. The tag is based on RFID technology, so in theory when you drive through the gate, the RFID is triggered to pulse its information to the gantry. This is the easy solution for e-tolling.

You will see that there are the black lights and cameras posted next to each other. The white area of a car's number plate is designed/painted to reflect black light which are then picked up by the cameras as a black and white image. You will also see that there are paint markings on the road under the gantry that are used as trigger points. The trigger points initiate the taking of pictures as well as determining the class of vehicle currently passing the gantry. They then have a server/s that process the images to retrieve the number plate, length of vehicle. They also take a picture of the vehicle as part of the record in case of a dispute from clients. The problem with number plate recognition is the fact that typical accuracy is 94% (to reach 98% accuracy starts costing so much its not feasible), which leaves a massive margin of undetectable plates. So if a plate can't be recognised automatically, they have to manually annotate the "toll" which will be at cost to them. I don't know what camera's they are using but we used to use ARHungary's product (currently running at ACSA aiports when you go into the parking area where you pull your ticket) which is incredibly fast, very accurate, but very very expensive. The one used for e-toll look like a cheaper solution. So SANRAL want you to use tags, because it makes they life very very easy in terms of maintenance and effort.

I hope someone finds this interesting.

Yup... this whole post exactly. One of the cameras will likely have an infrared (or UV) filter that will only pick up infrared or UV light. This way only the reflective part of the number plate is visible to the camera, making OCR easier. If it's infrared, it's easy to screw up the cameras with a few infrared LED's. I wonder if they are using the same concept but with UV though? They will have full colour images as well, so you need to obscure the plate in some way if you want to prevent manual detection by an operator... and not have an e-tag.

As for the tags... if they are RFID tech... they would have to be IPX tags as EPC tags are useless above 80km/h... and even IPX tags don't pick up over 160km/h (but if you are doing that through a gantry I guess you'd get a ticket if your plate didn't have mud:P) Also, the transmitters would have to be f'ing powerful to get any kind of decent range. I'd imagine that they'd have some kind of active tag technology to get the range they'd need.

Ja its not Infrared, the specs on the pamphlet say their normal illuminator is infrared, but they arent using that, you can see the light, so its not completely ultraviolet, it just seems to be some particular colour blue, but maybe it includes UV?

Need to know more because if it does include UV, and the camera records UV, then a clear film that reflects UV might obscure the plate but would not be easily detectable (ie appear transparent to naked eye).

I used to work in this field so I can give a basic idea. The tag is based on RFID technology, so in theory when you drive through the gate, the RFID is triggered to pulse its information to the gantry. This is the easy solution for e-tolling.

You will see that there are the black lights and cameras posted next to each other. The white area of a car's number plate is designed/painted to reflect black light which are then picked up by the cameras as a black and white image. You will also see that there are paint markings on the road under the gantry that are used as trigger points. The trigger points initiate the taking of pictures as well as determining the class of vehicle currently passing the gantry. They then have a server/s that process the images to retrieve the number plate, length of vehicle. They also take a picture of the vehicle as part of the record in case of a dispute from clients. The problem with number plate recognition is the fact that typical accuracy is 94% (to reach 98% accuracy starts costing so much its not feasible), which leaves a massive margin of undetectable plates. So if a plate can't be recognised automatically, they have to manually annotate the "toll" which will be at cost to them. I don't know what camera's they are using but we used to use ARHungary's product (currently running at ACSA aiports when you go into the parking area where you pull your ticket) which is incredibly fast, very accurate, but very very expensive. The one used for e-toll look like a cheaper solution. So SANRAL want you to use tags, because it makes they life very very easy in terms of maintenance and effort.

I hope someone finds this interesting.

Yup... this whole post exactly. One of the cameras will likely have an infrared (or UV) filter that will only pick up infrared or UV light. This way only the reflective part of the number plate is visible to the camera, making OCR easier. If it's infrared, it's easy to screw up the cameras with a few infrared LED's. I wonder if they are using the same concept but with UV though? They will have full colour images as well, so you need to obscure the plate in some way if you want to prevent manual detection by an operator... and not have an e-tag.

As for the tags... if they are RFID tech... they would have to be IPX tags as EPC tags are useless above 80km/h... and even IPX tags don't pick up over 160km/h (but if you are doing that through a gantry I guess you'd get a ticket if your plate didn't have mud:P) Also, the transmitters would have to be f'ing powerful to get any kind of decent range. I'd imagine that they'd have some kind of active tag technology to get the range they'd need.

So, all we need to do is avoid the trigger, which is in the middle of the lane, plain to see. If I were to go under a gantry while straddling the lanes, I will miss the trigger.

Whcih means they won't know I'm there coz I ain't got a tag either - worth a try?

Some very interesting info coming through, when photos start appearing in a month or two, they will give up valuable information so as to know exactly what we dealing with and what the actual capabilities are.

So as I understand it so far, a pic is taken from the front as well as the back, the software morphs the two together creating a 3D image which is then used to measure the length of the vehicle, as well as the height.The number plate is read via OCR software, and compared to the info on the transponder, if fitted, length and height of vehicle confirm correct class of vehicle.Cameras are mounted at roughly 30 degree angle, give or take.

This info opens the flood gates to valid disputes if known, as few questions remain unanswered, or maybe I missed them, but are of little matter anyhow.Which number plate does the OCR read and take the info from, front or back? Ok on a bike the back obviously, what about a car? front or back, or does it compare the two to verify, what if there are two different plates on the frno and the back? Will the OCR pick it up and flag it, or will it assume either front or back to be valid?

So here is the drill, read the traffic ahead when approaching a gantry, find a big truck, position yourself behind the truck and gradually start closing up on it, time it so that just before you are under the gantry you have closed right up and are slipstreaming the truck by about one or two meters, once through the gantry you can break off and continue on your way, if timed properly you only have to tail him by a meter or so for no more than 5-10 sec.

As I understand it, I assume that a meter will be close enough for the system not to be able to differentiate between the two vehicles, and thus the composite image will be of the two vehicles as a single vehicle.The cameras will see the trucks front number plate and your rear plate, thus throwing up two different numbers, being unable to see your front or the trucks rear plates.The vehicle length will be the sum of both vehicles and the height, that of the truck.One of two hings, the trucks front number plate is read and the info used, you get off Scott free, truck pays.Or, system uses the info from the back plate, (yours) and you get billed for an articulated vehicle sizeYou could have a field day disputing this one, and it would be valid disputes. I have been doing it foe a few days now, lets see, if I ever get any bills.

Your thoughts, am I missin something here?

Oh, and I made a point of looking today, the gantries at Giloolees, van Buuren and Rand Airport rd as well as the ones at Geldenhuis and opposite O.R Tambo do not have any equipment over the emergency lanes.